Side retort stoker



Nov 15, 1938. J; 5. SKELLY SIDE RETORT STOKER '3 Sheets-Sheet I FiledDec. 17, 1934 SLEQ/ENTOR Nov. 15, 1938. J. s. SKELLY SIDE RETORT STOKERFiled Dec. 17, 1934 3 SheetsrSheet 2 INVENTOR Novow, 1938. J. s. SKELLYSIDE RETORT STOKER Filed Dec. 17, 1934 3 Sheets-Sheet 3 atented Nov. 15,1938 UNITED STATES PATENT OFFICE 4 Claims.

This invention relates to underfeed stokers and more particularly tounderfeed stokers of the side retort type.

In underfeed stokers having a single horizontal retort positionedadjacent a side wall of a furnace [with an ash receiving grate at oneside only of the retort andtuyere blocks spanning the space between theretort and the ash receiving grates, there is a marked tendency for thefuel to m the adjacent furnace side well.

While a side retort stoker requires fewer parts, is somewhat simpler tooperate than a center retort stoker and allows the ash to be taken outat one point instead of two (as in the center retort stoker) thiscumulative piling up of the fuel has been found to be a markeddisadvantage of the side retort type and an object of this invention isto produce a side retort stoker which, while simple in construction,overcomes this piling up tendency of thefuel.

I have found that this tendency of the fuel to pile up above the retortin side retort stokers can be effectively overcome if certain of thetuyere blocks between the retort and the ash receiving grates are causedto reciprocate toward and ,from the retort in the proper amount to causefuel to move toward the ash receiving grate at the desired rate ofspeed, and another object of this invention is to produce a simple,rugged, adjustable means for reciprocating these tuyere blocks.

I find that for a given furnace area, that is, for given dimensionswithin a furnace fire box and with the same retort dimensions, I am ableto effectively burn more fuel on a side retort stoker than on a centralretort stoker.

Stokers embodying this invention are particularly adapted for sizes from25-200 H. P. and are particularly suitable for installations in placessuch as school buildings, apartment houses, office buildings, greenhouses and the like where it is not usual to employ skilled operators asin larger installations.

After much experimental work on single retort stokers and particularlythose of the side retort type, I have found that a screw conveyor is themost satisfactory feeding device for a wide variety of fuels and I havealso found that in addition to the reciprocating tuyere blocks on oneside of the retort for overcoming the piling up tendency above theretort it is most essential to incorporate, in the unit, means fordistributing and agitating the fuel within and above the re- 5| tort andan object of this invention is to produce cumulatively pile up above theretort'and against means operable from a single power shaft foroperating in a coordinated manner the screw conveyor, the reciprocatingtuyere blocks and the distributing and agitating means within theretort.

I find that it is necessary to so correlate and 5 coordinate thesedifferent agencies that each contributes its share to the properdistribution of the fuel, that is, the fuel conveyed to the retort, thefuel within and immediately above the retort m and the fuel burningsurfaces between the retort and the ash receiving grate and anotherobject of this invention has been to produce means whereby thesedifferent agencies can be properly correlated and coordinated to producea stoker 1 5 which will effectively burn slack, as well as a widevariety of other fuels.

I also find that it is necessary to vary the air feed to different partsof the fuel bed and a still further object is to provide simple meansfor allocating air under pressure to different parts of the fuel bed ina side retort stoker in the proper amounts to support combustion withoutblasting portions of the bed, blowing cold spots in other portions orholes in other portions.

These as well as other objects, which will readily appear to thoseskilled in this particular art, I attain by means of the stoker unitdescribed in the specification and illustrated in the drawingsaccompanying and forming part of this application.

In the drawings:

Figure 1 is a view partially in side elevation and partially in section(and with some parts broken away), of a side retort underfeed stokerembodying this invention. This view shows some of the tuyere blocks aswell as a portion of the retort side wall on the ash grate side of thestoker broken away;

Fig. 2 is a top plan view of portions of t e stoker illustrated in Fig.1 with certain of the tuyere'blocks removed. The fuel feeding mechanism,the fuel reservoir or hopper and associated. parts have been omitted anda portion of the ash supporting grates has been broken away;

Fig. 3 is an enlarged view in section, more or Fig. 4 is an enlargeddetail view in side elevation of one of the stationary tuyere blockslocated between the retort and the ash grates. This view shows itsposition with relation to the rock shaft for reciprocating the movabletuyere blocks;

Fig. 5 is a detail view partially in section and partially in endelevation of the rock shaft and part of its operating mechanism;

Fig. 6 is a view partially in section and partially in elevation of theparts shown in the central portion of Fig. 3, viz., the tuyere blocks,the rock shaft and part of its operating mechanism, a part of one retortside wall and a part of the wind box wall. This view shows the positionof the movable tuyere block at the end of its movement away from theretort.

Fig. '7 is a top plan view of part of the mechanism shown in Fig. 6;

Fig. 8 is an enlarged detail view in end elevation of one of the supportmembers for one of the bearings for the rock shaft. This view includespart of the mechanism for operating the rock shaft; and

Fig, 9 is a view in side elevation of the tuyere block shown in Fig. 4,but taken from the other side and turned end for end.

In the stoker I have chosen for the purpose of illustrating myinvention, the retort I is U- shaped in transverse section as shown inFig. 3 and is elongated (Fig. 2) and provided with a sloping inner endwall II. The top surrounding edge of the retort is provided with anoutwardlyextending flange I2 and the retort is provided with supportlegs l3 which rest upon the floor i4 of the wind box. Upright wall I 5of the wind box is spaced away from the retort to provide an air channelfor supplying tuyere blocks IS with air under pressure. The upper edgeof side wall l5 of the wind box is provided with an inwardly extendinglip or flange i! which cooperates with flange l2 of the adjacent retortside to support the tuyere blocks.

Side wall l5 of the wind box is adapted to lie against one side wall iiof the furnace within which the stoker is installed. Tuyere blocks l6fill the space between wall l8 of the furnace and the inner adjacentedge of the retort. These tuyere blocks have their inner surfaces l9curved and each block is preferably provided with a number of airdischarge channels for directing air under wind box pressure to the fuellying above the retort.

Each of these tuyere blocks has a central partition 2l'which extendsdownwardly below the I body of the block and terminates in a T-shapedend 22 which cooperates with flanges I2 and H to lock the tuyere blockagainst upward movement.

Side wall 23 of the wind box is provided with an inwardly extendingflange 24 along its upper edge and this wall is spaced away from itsside of the retort a suflicient distance to accommodate relatively longtuyre blocks 25 and 26.

Tuyere blocks 25 (see Figs. 3, 3a, 3b, 6 and 9) areprovided with oneflat side 21 and certain of these blocks 25 are made as rights whilecertain of them are made as lefts, that is, cer

tain of the blocks have projecting ledges or supports 28 and 29 whichextend outwardly in one direction from the flat side 21 while certainothers have corresponding ledges projecting in the opposite directionfrom their flat side 21. This is clearly shown in the right half portionof Figure 1 in which alternate stationary tuyere blocks beginning at theright-hand side of Figure l have their flanges 26 and 29 extendingtoward the left while the other stationary tuyere blocks have theirflanges 28 and 29 extending toward the right. This is also clearly shownin Fig. 3b. Below each such ledge portion the block is provided with adownwardly extending narrow hook-like member; that below ledge 28 isnumbered 30 and that below ledge 29 is numbered 3|. These hooklikemembers are adapted to hook under flanges i2 and 24 respectively, andlock these stationary tuyere blocks 25 against upward movement.

The upper surface of each of the flanges 28 and 29 is smooth and flatand forms a bearing surface upon which tuyere blocks 26 are supportedfor reciprocation within the channel formed by a pair of stationarytuyere blocks 25 as shown in Figs. 2, 3b and 6.

Approximately midway between the ends of each of the tuyere blocks 25and projecting laterally from the side opposite its flat side a verticalpartition 32 extends from the roof or fuel supporting portion thereof toa sealing flange 33 located at the bottom of the central partition 21.This sealing flange extends across the tuyere block for the full widththereof. Thelower curved surface 34 of each of the sealing flanges isformed on the arc of a circle for a purpose to be hereinafter described.Partition 32 is provided with an air discharge passage 35. The upper orfuel supporting surface of each of the tuyere blocks 25 is provided witha series of air channels 36 between flange 29 and partition 32 and thefuel supporting surface between partition 32 and flange 28 is providedwith a series of air discharge channels 31 and another series 38.Channels 38 direct air into the fuel bed above the retort.

Extending outwardly from the flat side of each stationary tuyere block25 are lugs or flanges 39 and 40 for a purpose as hereinafter set forth.Each of the movable tuyere blocks 26 is provided with a centralpartition or wall 4| and on each side of this wall is provided with avertically extending rib 42. These ribs at their lower ends join aninverted U-shaped or bifurcated member 43 which extends across the blockand forms its lower extremity serves as means for connecting the tuyereblock to the projecting flange of the rock shaft to be'described later.The rock shaft causes the movable tuyre blocks to reciprocate as it isoscillated.

Horizontal shelves 44 extend laterally from central rib 42 on oppositesides of central partition 4i and central partition 4| extendsdownwardly on each side of the inverted U-shaped member 43. Each of themovable tuyere blocks 26 is provided with a series of air channels 45for projecting air directly into the fuel above the retort; a series ofair directing channels 46 for directing airinto the fuel above theretort and also to that portion of the fuel bed supported by the innerportions of the tuyre blocks and these tuyere blocks also have a seriesof air discharge channels 41 for discharging air into the shallowerportion of the fuel bed above the tuyere blocks. Lugs or flanges 39 and40 which project laterally from the flat side of each tuyere block 25retain the movable tuyere blocks in place on supporting flanges 28 and29 of tuyere blocks 25. Flanges 39 lie aboveflanges 44 of tuyere blocks26 and flanges 4!! lie above laterally projecting bottom flanges 48 oftuyere blocks 26 as clearly shown in FigureBb.

.The stoker unit of this invention is preferably operated by a variablespeed driving mechanism such asdisclosed in my application which isserially numbered 706,040. As in said application, the blower forsupplying the wind box with air under pressure is directly coupled tothe motor which drives the variable speed mechanism. The variable speedmechanism is provided with a power shaft (Figure 1) and this shaft bymeans of a suitable coupling, is connected to a shaft 5I of conveyorscrew 52.

The inlet end of the feed screw is that portion located below the outletof the hopper-like fuel storage magazine 53. The outlet of the magazineis controlled by means of a slide 54 which acts as a gate for stoppingthe flow of fuel from the magazine to the inlet end of the feed screw.

The feed screw is located within a tubular housing 55 which passesthrough the end wall 56 of the retort I0. rounds housing 55 and servesas a conduit for conducting air under pressure delivered by the blowerto the wind box whichsurrounds the retort.

A rock shaft 58 which is circular in transverse section in the main, isprovided with an upwardly extending flange 59 which extends throughoutits length, except at its extreme end portions. This shaft is mountedbelow the stationary and movable tuyre blocks 25 and 26 and within thespace between the side wall 23 of the wind box and the adjacent side ofthe retort I0. The rock shaft parallels the wind box side 23 and theretort side and at its rear end is mounted in a bearing block 60 securedto the rear end Wall GI of the wind box. At its front end this shaft isjournaled in a bearing 62 formed in a block 63 bolted to front wall 04of the wind box. This latter bearing as shown in Fig. 8, has an open topso that the shaft, after having its rear end entered in bearing 60 canbe lowered into place with the front end cylindrical portion 58 enteringthe bearing 62 which cylindrical portion is held in position by capmember 65 which in turn is held in place by a bar 66.

Upstanding flange 59 on the rock shaft extends into inverted U-shapedmembers 43 on the movable tuyre blocks and as the shaft is oscillated,the top of this flange describes the arc of a circle which lies close tothe curved undersurfaces 34 of sealing flanges 33 on the stationarytuyre blocks 25.

The rock shaft adjacent its forward end and just behind its bearing 62is provided with a projecting arm 61. This arm is drilled at its centerto form concentric bores of two diameters. The larger bore is tapped toreceive the threaded portion 59 of a pin 68 and the smaller portion Illsnugly fits the inner smaller bore. That portion of the pin whichprojects beyond the outer end of stub shaft 61 carries a bearing ball IIwhich is held in place by means of the head I2 of pin 68.

Block 63 is provided with a partially cylindrical portion I3 whichextends laterally therefrom and is drilled to receive a stub shaft I4and on this, the hub 15 of a bell crank lever is mounted. The upper arm16 of this lever is provided at its forward end with a box-like portion,I'I which has a rectangular opening within which ball TI is located. Theother arm I8 of the bell crank lever projects downwardly and has itslower end I9 bifurcated as shown in Figs. 5 and 8. This bifurcated endis coupled by a coupling device to a connecting rod which is mounted forlongitudinal reciprocation toward and from the retort. The couplingdevice comprises a link 8| connected by means of a pin 82 to arm I8 andAnother housing 5'! sur- .the stationary tuyre blocks has its forwardend drilled and tapped to receive a screw threaded stem 83 of a lostmotion connectlng member 04. This member 84 is provided with anelongated slot 85 into which extends a pini 86 carried at the inner endof the connecting r0 Connecting rod 80 adjacent its rear end carries alaterally extending pin 86 which lies within slot 85. Surrounding pin 86between member 84 and a plate 81 bolted to the side of the connectingrod is a tubular spacer 88. This serves to space lost motion member 84from plate 81.

By placing take-up liners (not shown) within slot 85 of lost motionmember 84, the amount of lost motion between connecting rod 80 and armI8 of the bell crank lever may be adjusted. In this way just the rightamount of travel of the reciprocating tuyere blocks 26 is obtained. Theforward end of connecting rod 80 carries a vertically extending pin 89and upon this a tapered cam follower or roller 90 is mounted. Thistapered roller is positioned within a continuous groove 9| formed in theperiphery of a cam wheel 92. The continuous groove 9! has flared sidescorresponding to the taper of cam follower 90. The clearance between thefollower and the flared sides is such that the follower may run freelywithin the groove without binding.

Groove M is disposed at an angle to the plane that is perpendicular tothe axis of'shaft 50 so that as the cam wheel is rotated, connecting rod80 will be given a back and forth longitudinal reciprocation. I

The fuel agitator located within the retort and which not only agitatesthe fuel within the retort and that above the same, but also distributesthe fuel so as to form a homogeneous mass, comprises a reciprocating bar93 which is supported at the front and rear ends of the retort by wearplates respectively numbered 94 and 95. This bar on its upper surfacescarries agitating and distributing members 95 and 91. The forward end ofbar 93 by means of connecting plates 81 and 98 and suitable bolts asshown in Figs. 1, 6 and 7 is coupled to connecting rod 80.

Reciprocating bar 93 passes through an opening 99 formed for thatpurpose in slopingend wall II of the .retort.

The ash receiving and disposal grates I00 may be of any desired designor construction so long as they are of adequate size and design tosupport the ash between periods of dumping.

Sealing flanges 33 on the stationary tuyre blocks 25 as I have said, liein close proximity to the top of longitudinal flange 59 on rock bar 58and these flanges are sufliciently long from front to rear to cover thefull movement of flange 59 on the rock bar. These flanges, together withmembers 43 on the movable tuyere blocks which straddle flange 59 of therock bar and a sheet metal partition plate IOI which extends from side23 of the wind box to a point I02 which is beyond the center of the rockbar prevents Wind box air from reaching air channels 41 of the movabletuyre blocks 26 and air channels 36 of 25, except by way of ports 35 inpartitions 32 of the stationary tuyre blocks 25 and openings I03 in ribs42 of the movable tuyre blocks 26.

Partition plate IOI is held in position and in contact with thecylindrical under surface of the rock bar during its oscillation bymeans of a spring member I04 which is secured to the wind box side andbears against plate I 0|.

Having thus described my invention, what I claim as new and desire tosecure by Letters Patent is:

1. In an underfeed stoker, an elongated horizontal retort, tuyere blockson opposite sides thereof and of which at least some on one side 7 aremounted for reciprocation toward and from.

the retort, a screw conveyor for feeding fuel into the retort, a fuelfeeder and agitator mounted for reciprocation within and longitudinallyof the retort, a rock shaft having operative connection with the movabletuyere blocks, a power shaft for rotating the screw conveyor, a camwheel carried by said shaft, a connecting rod operated by said cam wheelfor reciprocating said fuel feeder and agitator and agents between saidrock'shaft and connecting rod for oscillating said shaft.

2. In an underfeed stoker, a horizontal retort, tuyre blocks on oppositesides of the retort with certain of the same on at least one sidethereof mounted for reciprocation toward and from the retort, a screwconveyor for feeding fuel into the retort, a rotatable power shaft towhich said conveyor is coupled, an agitator and fuel feeder mounted forreciprocation within and longitudinally of the retort adiacent itsbottom, a cam wheel carried by said power shaft, a connecting rodreciprocated by said cam wheel and coupled to said agitator and fuelfeeder and means also coupled to said connecting rod for oscillatingsaid rock shaft.

3. In an underfeed stoker, an elongated horizontal retort, tuyere blockson at least one side thereof and some of which are mounted forreciprocation toward and from the retort, ascrew conveyor for feedingfuel into the retort, a fuel feeder and agitator mounted forreciprocation within and longitudinally of the retort, a rock shafthaving operable connection with the movable tuvere blocks, a power shaftfor rotating the screw conveyor, a cam wheel carried by said shaft, aconnecting rod operated by said cam wheel for reciprocating said powerfeeder and agitator and agents between said rock shaft and connectingrod for oscillating said shaft.

4. In an underfeed stoker, a horizontal retort,

-tuyere blocks on at least one side of the retort with certain of thesame mounted for reciprocation toward and from the retort, a screwconveyor for feeding fuel into the retort, a rotatable power shaft towhich said conveyor is coupled, an agitator and fuel feeder mounted forreciprocation within and longitudinally of the retort adjacent itsbottom, a cam wheel carried by said power shaft, a connecting rodreciprocated by said cam wheel and coupled to said agitator and fuelfeeder and means also coupled to said connecting rod for oscillatingsaid rock shaft.

JOHN S. SKELLY

